Having knowledge (of) (5)
I believe the answer is:
aware
'having knowledge of' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for aware that I've seen before include "Acquainted with or mindful of" , "Conscious, knowing about" , "Apprised or informed" , "Acquainted with or conscious of" , "Informed; conscious" .)